This disclosure is generally directed to toner processes, and more specifically, emulsion aggregation and coalescence processes, as well as toner compositions formed by such processes.
Toner blends containing crystalline or semi-crystalline polyester resins with an amorphous resin have recently been shown to provide very desirable ultra low melt fusing, which is important for both high-speed printing and lower fuser power consumption. These types of toners containing crystalline polyesters have been demonstrated suitable for both emulsion aggregation (EA) toners, and in conventional jetted toners. Combinations of amorphous and crystalline polyesters may provide toners with relatively low-melting point characteristics (sometimes referred to as low-melt, ultra low melt, or ULM), which allows for more energy-efficient and faster printing.
Emulsion aggregation/coalescing processes for the preparation of toners are illustrated in a number of patents, such as U.S. Pat. Nos. 5,290,654, 5,278,020, 5,308,734, 5,344,738, 6,593,049, 6,743,559, 6,756,176, 6,830,860, 7,029,817, and 7,329,476, and U.S. Patent Application Publication Nos. 2006/0216626, 2008/0107990, 2008/0236446, and 2009/0047593. The disclosures of each of the foregoing patents are hereby incorporated by reference in their entirety.
To produce thinner toner layers on prints, it may be desirable to increase the pigment loading in these toners. The resulting toners, sometimes referred to as “highly pigmented” toners, may be more economical than conventional EA toners, as lower amounts of toner may be required to obtain quality images. However, the high pigment loading may make it difficult to achieve the desired particle shape (circularity). In addition, longer times for forming the particles and higher coalescence temperatures may be required.
Improved methods for producing toner particles, reducing the time and cost involved in producing the toner particles, remain desirable.